Technical Field
The present invention relates to photovoltaic devices and methods for fabrication, and more particularly to systems, devices and fabrication methods that improve efficiency by employing dual power deposition steps.
Description of the Related Art
A barrier height is a difference between work functions of different materials. The barrier height is affected by the type of material with which the semiconductor is in contact. A band offset is the measure of misalignment between energy levels at the interface between two solids. The offset between an electrode and a semiconductor is called a “Schottky barrier”. The barrier height and offset are measures of how much a given material resists the flow of electrical charge through a medium. Both semiconductor-semiconductor band offset and semiconductor-electrode Schottky barrier decrease solar cell efficiency.
To improve solar efficiency, barrier heights and barrier offsets may be addressed by material selection. However, material selection alone is often inadequate as an appropriate material may not exist with the required characteristics to provide an optimal transition in energy bands between adjacent materials.